Coast guard solves vibration problem with Thordon propeller shaft bearing system
The Canadian Coast Guard (CCG) has again selected Thordon Bearings’ COMPAC water lubricated propeller shaft bearing system for two icebreakers, one of which has recently completed extensive upgrade work at the Chantier Davie Canada shipyard, in Lévis, Québec.
CCG, a long-standing customer of Thordon Bearings, decided to retrofit the award-winning COMPAC system to the 6098gt Des Groseilliers following more than 17 years’ operational experience with the Thordon solution. The new COMPAC bearings were supplied and machined by Thordon distributor RMH Industries of Québec, Canada, and fitted by the Chantier Davie Canada shipyard.
Des Groseilliers’ 5910gt sister, CCGS Pierre Radisson, is scheduled to have its existing dovetail staves replaced with Thordon full form COMPAC bearings later in 2018. These will again be supplied and machined by RMH Industries, along with supply of a Thordon Water Quality Package which maintains the correct seawater flow rate to the bearings, and removes any abrasives in the seawater ensuring a long bearing wear life.
The Pierre Radisson was launched in 1978, while the 6098gt Des Groseilliers entered service four years later.
Both vessels are powered by a diesel-electric plant comprising six Bombardier/Alco 251 engines each driving a GEC alternator. There are two DC electric propulsion motors, each turning a fixed pitch propeller, with a total power output of 10,100kW.
Jasmin Racicot, Technical Development Director of RMH Industries, said: “The Thordon COMPAC bearings were fitted to the Des Groseilliers to replace another manufacturer’s dovetail staves. Wear and fatigue had led to the dovetail staves becoming loose between the bronze separators, leading to high levels of vibration. Replacing dovetail staves with tube bearings was a significant improvement in this situation.”
Thordon’s Scott Groves, Regional Manager for the Americas, pointed out that for once the environmental advantages of water-lubricated bearings, particularly for vessels engaged in Arctic voyages, were not a factor, as this class of ship has always had seawater lubricated screwshafts.
“The work on the Des Groseilliers and Pierre Radisson mostly have to do with reduced maintenance and limiting future expenditures,” said Groves. “Des Groseilliers was fitted with Thordon equipment in 2001 and over the years the bearings have performed in exemplary fashion.
“Switching to Thordon COMPAC bearings and Water Quality Packages allows an extension in bearing life, giving the Coast Guard reliable access to the asset, and ultimately savings to the Canadian taxpayer, thanks to greatly reduced maintenance costs.”
Groves added that it was COMPAC’s performance and ease of maintenance that were most attractive to the CCG, along with the recent class requirements for shaft condition monitoring (SCM).
A third CCG ship in the 1200-class is also scheduled for COMPAC conversion. Commissioned in 1979 as the Franklin (later Sir John Franklin), the vessel was declared surplus to requirements and decommissioned in 2000. It was subsequently converted to an icebreaking Arctic scientific research vessel, renamed Amundsen, and recommissioned in 2003. The Amundsen is expected to be converted to Thordon COMPAC bearings in 2019.